August 2009:News & Notes

- The LRO Photographs the Apollo landing sites: Fans of this space may have noticed the racy lunar pics we ran a week back as part of our From Earth to the Moon review. The Lunar Reconnaissance Orbiter did indeed snap pics of the famous Apollo landing sites last month. These clearly show the hardware left at multiple sites, as well as the base(s) of the Lunar Lander ascent stages, complete with shadow. You can even see the astronaut’s foot trails in the lunar dust! And the LRO hasn’t even entered its cruising orbit yet… expect more great pics to come!

A “Cool” telescope heats up: One of the great orbiting observatories of our era is wrapping up its primary mission. The Spitzer Space Telescope has used up the remainder of coolant it carries and will now function through its final years in the near-infrared only. Placed in a receding Earth trailing solar orbit, Spitzer is out of range for a Hubble style repair mission. Without its on-board supply of liquid helium, Spitzer’s detectors have warmed up to “only” 31 kelvins. Launched in 2003, Spitzer has out performed all expectations, spotting possibly the youngest star ever seen, IR light (and weather patterns!) on a “hot-Jupiter,” and yet more evidence that our galaxy is indeed a barred one… Spitzer may just well prove to be the greatest space telescope that you’ve never heard of!

Galactic X-Ray Mystery Solved?:…and speaking of orbiting observatories, Spitzer’s X-ray twin, Chandra, has made stunning discoveries of its own… one of which is a long standing problem with X-ray emissions along the galactic plane. Specifically, a “Galactic ridge” outlined by X-ray emissions has been observed over the last few decades extending 2 degrees above and below and 40 degrees to either side of the galactic plane. Chandra can resolve these sources in greater detail to spot no less than 473 distinct x-ray sources dotting the galactic core. Possible suspects include magnetically active white dwarfs. These visually span a selected study patch about 3% the apparent size of a Full Moon.

The Earth through Alien Eyes: Ever wonder if E. T.s looking at our solar system could detect us? The results might surprise you… in the visible spectrum, markers such as free oxygen and methane (produced largely by bovine flatulence!) may be their first clues that something interesting is transpiring on Earth. Now scientists at NASA have re-assigned the Deep Impact probe to look back at Earth, perhaps mimicking what we would see from light years away. This sort of study will be useful as we identify Earth-like candidates in the decades to come. Shrinking the rotating gibbous Earth to a single blue-white pixel, scientists were able to construct a basic “strip map” as the planet turned on its axis. While at first not very amazing, this would reveal a dynamic world of clouds, land, and sea, not the boring homogeneity of other terrestrial planets such as Venus or Mars. On this scale, the proposed ATLAST space telescope, armed with a 16-meter mirror, could map Earth-like worlds up to about 30 light years away. Intelligent bovine species, take note…

Uncovering millisecond pulsars: Pulsars present a mystery in radio astronomy. Remnants of massive supernovae, these rotating beacons generally spin down over millennia. A sub-class, however, known as milli-second pulsars, seem to be actually sped up, rotating hundreds of times a second. Now, scientists at the Green Bank Radio Telescope and and the Very Large Array in Socorro, New Mexico may have caught one in the act; J1023, a pulsar in a binary system about 4,000 light-years distant. Snapshots in 1999, 2000, and 2002 show a rapidly evolving system, a seemingly sun-like star gradually revealing itself through a fading accretion disk to be a millisecond pulsar spinning at 592 times per second. The dumping of accretion material by a companion star has long been thought of as the culprit in the spin up, via the law of conservation of angular momentum. This is, however, the first time astronomers have actually witnessed such a beast in action. J1203 is orbited by its companion once every 4.75 hours.

Pinning down Type 1a supernovae: When we’re talking extra-galactic distances, Type 1A supernovae have become the coin of the realm. These supernovae behave in a well known fashion and provide a method to compare and measure the distance to their host galaxies. Now researchers at the Laboratory of Nuclear and High-Energy Physics in Paris have combed data from the Nearby Supernova Factory to produce a quicker and more accurate method to pin down cosmic distances; known as the 642/443 method due to the wave lengths it compares, it has a margin of error of 6% and can be done based on the spectra collected in a single night. It is also independent of interference by galactic dust. This method will go a long way towards smoothing out the Hubble Constant as well as the effects of dark energy on the expansion of the universe.

Dark Matter(s): Not to be outdone, astronomers at the Supernova H0 for the Equation of State (SHOES) team have pegged down an even older and more cherished cosmic yard stick; Cepheid variables. This particular class of variable star changes luminosity in a predictable way, and if they can be identified in nearby galaxies, intrinsic distances can be known. Using the Hubble Space telescope, the SHOES team has refined this yard stick to some very distant galaxies and in the process brought the expansion rate of the universe, known as the Hubble Constant, down to 74.2 km per second per mpc, within a factor of plus or minus 3.6. This in turn will hopefully paint a picture of how dark energy has played a role in speeding up the expansion of the universe.

Towards a Better, “Beefier” Milky Way?:(Jan 25) One thing has become clear over the last decade; we don’t live in your father’s Milky Way galaxy. New astrometry results conducted with the Very Long Baseline Array have revealed that our galaxy is rotating about 270 kilometers per second, 15% faster than was previously thought; this fact may mean something startling; our galaxy may be on the order of size of our neighboring Andromeda galaxy! Its a shame someone “over there” can’t email mail us a snapshot of ourselves… this study used the parallaxes of 18 radio sources to conduct the survey. And the baseline utilized is VERY long… think from Hawaii to New Hampshire! And now there’s pretty good evidence (see above) that we’re a barred spiral to boot… of course your grandfather’s Milky Way was thought to be the entire universe!

Launches for August: The big launch on the ticket out of the Kennedy Space Center (KSC) is the Shuttle Discovery on STS-128 for Aug 25th (a predawn launch!) Unfortunately, the much anticipated first unmanned test flight of the Ares X-1 slipped to the 31st of October. And it was almost starting to seem real now! Next door at the Cape, a Delta 2 will launch another NAVSTAR satellite on the 17th. Another classified launch at the Cape occurs on the 12th. Be sure to check Spaceflight Now for all of the latest updates!

Astro-Blooper of the Month: An oldie but goodie came back to my attention re-watching the Star Trek: Enterprise series finale; in a key scene, Enterprise races towards Mars as a comet streaks towards the Red Planet… the tail, however, is facing the wrong way! With a gibbous Mars giving away the Sun’s position off to the right of the viewer, the tail should have been streaming off to the left. It’s bizarre, I know, but solar wind sweeps the comets tail away from the nucleus, often ahead of its own orbit!

This Month in Astro-History: On August 12, 1977 the 1st free flight of a Space Shuttle was conducted at the dry lake bed test facility at Edwards AFB. The shuttle was Enterprise, which was initially intended to eventually be retrofitted for space flight but of course, never flew in space. It currently resides at Smithsonian’s Steven F. Udvar-Hazy Center at the Dulles Air Port. And to think, I’m actually old enough to remember watching this short flight!.

Quote of the Month: The universe is full of magical things patiently waiting for our wits to grow sharper.”

Astro Documentaries

Pictured is a Delta IV rocket launch from Cape Canaveral on November 21st, 2010. The image is a 20 second exposure taken at dusk, shot from about 100 miles west of the launch site. The launch placed a classified payload in orbit for the United States Air Force.

DIY Astronomy

Difficult but not impossible to catch against the dawn or dusk sky, spotting an extreme crescent moon can be a challenge. The slender crescent pictured was shot 30 minutes before sunrise when the Moon was less than 20 hours away from New. A true feat of visual athletics to catch, a good pair of binoculars or a well aimed wide field telescopic view can help with the hunt.

The Sun is our nearest star, and goes through an 11-year cycle of activity. This image was taken via a properly filtered telescope, and shows the Sun as it appeared during its last maximum peak in 2003. This was during solar cycle #23, a period during which the Sun hurled several large flares Earthward. The next solar cycle is due to peak around 2013-14.

Astronomy Gear Reviews

Located in the belt of the constellation Orion, Messier 42, also known as the Orion Nebula is one of the finest deep sky objects in the northern hemisphere sky. Just visible as a faint smudge to the naked eye on a clear dark night, the Orion Nebula is a sure star party favorite, as it shows tendrils of gas contrasted with bright stars. M42 is a large stellar nursery, a star forming region about 1,000 light years distant.

Astronomical Observing Targets

Orbiting the planet in Low Earth Orbit (LEO) every 90 minutes, many people fail to realize that you can see the International Space Station (ISS) from most of the planet on a near-weekly basis. In fact, the ISS has been known to make up to four visible passes over the same location in one night. The image pictured is from the Fourth of July, 2011 and is a 20 second exposure of a bright ISS pass.

Next to the Sun, the two brightest objects in the sky are the Moon and the planet Venus. In fact, when Venus is favorably placed next to the Moon, it might just be possible to spot the two in the daytime. Another intriguing effect known as earthshine or ashen light is also seen in the image on the night side of the Moon; this is caused by sunlight reflected back off of the Earth towards our only satellite.

A mosaic of three images taken during the total lunar eclipse of December 21st, 2010. The eclipse occurred the same day as the winter solstice. The curve and size of the Earth’s shadow is apparent in the image.